The present invention relates to a device for the display of data representative of quantities such as for example reference values, results of calculations or even measurement values.
Generally, there are currently two main types of display devices of this type, namely so-called analog display devices and so-called digital display devices.
Analog display devices which most frequently consist of a graduated dial and a reference mark able to move one with respect to the other, have numerous advantages.
Primarily, they make it possible to provide the operator not only with the purely abstract value of the quantity displayed, but with a concrete representation of this value which is provided by the position and behaviour of the reference mark with respect to the graduation of the dial and/or with respect to reference members, of very varied type, appearing on the dial or outside the latter.
However, the main drawback of these systems emanates from the fact that they use electro-mechanical processes which are generally slow and delicate and which are ill-suited to digital processing systems since they are based on analog signals.
Digital display devices which make it possible to obtain a direct display in numbers, may be more accurate and require no extrapolation, which would be the case for example when in an analog display device, the reference mark indicates a value comprised between two graduations (in fact, in a digital device, it is possible to provide a number of decades corresponding to the required accuracy).
These systems also have the advantage of requiring only electronic or opto-electronic devices, thus excluding any electro-mechanical device.
However, it is only possible to obtain abstract values with these systems and this is excluding any other indication for example facilitating a rapid evaluation of what these values represent themselves and with respect to reference members which are significant for the operator.
Furthermore, even if these digital systems provide incomparable results in the display of a fixed quantity, for example the result of a mathematical operation, this is not so as regards the display of a quantity varying with respect to time. In fact, continual or repeated flashing of the last decade of the numbers displayed makes reading of the value at a given instant difficult and constitutes a hidrance to the operator.
This drawback is all the more considerable since in a general manner operators assigned to supervising a process, or even pilots, in the case of flying an aerodyne, must pay attention to any flashing of a light. In fact, flashing of this type must frequently indicate the presence of a breakdown, an anomaly or the starting point of an operation which the operator or pilot must carry out.
Furthermore, on account of the absence of a reference member, these digital devices do not allow the operator to estimate quantitatively or qualitatively a variation in the quantity measured (quantitative estimation possibly being the estimation of a deviation and qualitative estimation possibly being the variation speed).
The invention therefore relates to a display system which makes it possible to combine the advantages of the two aforementioned types of display system.